TNFR1
TNFR1 is a transmembrane receptor containing an extracellular region that binds ligand and an intracellular domain that lacks intrinsic signal transduction activity but can associate with signal transduction molecules. The complex of TNFR1 with bound TNF contains three TNFR1 chains and three TNF chains. (Banner et al., Cell, 73(3) 431-445 (1993).) The TNF ligand is present as a trimer, which is bound by three TNFR1 chains. (Id.) The three TNFR1 chains are clustered closely together in the receptor-ligand complex, and this clustering is a prerequisite to TNFR1-mediated signal transduction. In fact, multivalent agents that bind TNFR1, such as anti-TNFR1 antibodies, can induce TNFR1 clustering and signal transduction in the absence of TNF and are commonly used as TNFR1 agonists. (See, e.g., Belka et al., EMBO, 14(6):1156-1165 (1995); Mandik-Nayak et al., J. Immunol, 167:1920-1928 (2001).) Accordingly, multivalent agents that bind TNFR1 are generally not effective antagonists of TNFR1 even if they block the binding of TNFα to TNFR1.
SEQ ID numbers in this paragraph refer to the numbering used in WO2006038027. The extracellular region of TNFR1 comprises a thirteen amino acid amino-terminal segment (amino acids 1-13 of SEQ ID NO:603 (human); amino acids 1-13 of SEQ ID NO:604 (mouse)), Domain 1 (amino acids 14-53 of SEQ ID NO:603 (human); amino acids 14-53 of SEQ ID NO:604 (mouse)), Domain 2 (amino acids 54-97 of SEQ ID NO: 603 (human); amino acids 54-97 of SEQ ID NO:604 (mouse)), Domain 3 (amino acids 98-138 of SEQ ID NO: 603 (human); amino acid 98-138 of SEQ ID NO:604 (mouse)), and Domain 4 (amino acids 139-167 of SEQ ID NO:603 (human); amino acids 139-167 of SEQ ID NO:604 (mouse)) which is followed by a membrane-proximal region (amino acids 168-182 of SEQ ID NO:603 (human); amino acids 168-183 SEQ ID NO: 604 (mouse)). (See, Banner et al., Cell 73(3) 431-445 (1993) and Loetscher et al., Cell 61(2) 351-359 (1990).) Domains 2 and 3 make contact with bound ligand (TNFβ, TNFα). (Banner et al., Cell, 73(3) 431-445 (1993).) The extracellular region of TNFR1 also contains a region referred to as the pre-ligand binding assembly domain or PLAD domain (amino acids 1-53 of SEQ ID NO:603 (human); amino acids 1-53 of SEQ ID NO:604 (mouse)) (The Government of the USA, WO 01/58953; Deng et al., Nature Medicine, doi: 10.1038/nm1304 (2005)).
TNFR1 is shed from the surface of cells in vivo through a process that includes proteolysis of TNFR1 in Domain 4 or in the membrane-proximal region (amino acids 168-182 of SEQ ID NO:603; amino acids 168-183 of SEQ ID NO:604), to produce a soluble form of TNFR1. Soluble TNFR1 retains the capacity to bind TNFα, and thereby functions as an endogenous inhibitor of the activity of TNFα.
WO2006038027, WO2008149144 and WO2008149148 disclose anti-TNFR1 immunoglobulin single variable domains and antagonists comprising these. These documents also disclose the use of such domains and antagonists for the treatment and/or prevention of conditions mediated by TNFα. It would be desirable to provide anti-human TNFR1 immunoglobulin single variable domains with improved storage stability, antagonists, ligands and products comprising these. The aim of these would be to provide improved diagnostic reagents for detecting human TNFR1 in samples, as well as or alternatively to provide improved therapeutics for the treatment and/or prophylaxis of TNFR1-mediated conditions and diseases in humans or other mammals. It would be particularly desirable to provide anti-TNFR1 immunoglobulin single variable domains, antagonists, ligands and products comprising these that are potent neutralizers of TNFR1, especially of human TNFR1
The various aspects of the present invention meet these desirable characteristics.